UKC

Does anyone know the rope diameter limits for an original petzl Grigri? I am looking at buying a new rope of about 9.8mm and don’t know if my original Grigri will hold that diameter.

I’ve been on the Petzl website but can’t find any info on the original Grigri.

Thanks in advance for any advice👍

10-11mm

Lots of people use them with skinnier ropes, buts it’s your choice.

It changed from 10-11mm to something lower halfway theough it's life but 9.8 is normal.

I once tested original Gri Gri with Mammut Serenity 8.9 rope and it did lock. I used it with 9.5 Infinity on regular basis - no issues whatsoever.

You'll be fine with 9.8.

As above 9.8 will work absolutely fine. I've used one with a 9.0 and it also worked without problems. 

Some historical info for you:
https://blog.momentumclimbing.com/innovations-in-climbing-the-grigri/
https://www.petzl.com/US/en/Sport/News/2015-7-22/The-GRIGRI-belay-device--a...
http://storrick.cnc.net/VerticalDevicesPage/BelayDevices.shtml

Gary Storrick's website is a treasure trove of info...and I like how he has dedicated his work to the memory of Bob Thrun who was a legendary man (and the discoverer of the incredible Zeppelin bend).

The GriGri is a self-braking device - conforming to the EN15151-1 (since 2012) which further differentiates between 'manual braking devices' and 'Braking device with manually assisted locking' (which further vary from 'type 1', through to 'types 5').

Original (first gen) version of GriGri was 10.0mm-11.0mm.
Second gen was 8.9mm-11.0mm
Third gen is 8.5mm-11.0mm

As EN892 dynamic ropes got thinner, Petzl (and the competition) have tried to keep up.
Current thinnest EN892 certified single rope is 8.5mm diameter.
Obviously, when the next evolutionary leap to sub 8.5mm occurs, Petzl will scramble to release a 4th gen version! (and so will the competition). The military are already lead climbing with 6.0mm cord using the CTOMS 'quickie' belay device. Bit of an eye popping experience to lead climb on a single strand of rope/cord that is sub 8.0mm!

I would comment that a commercial enterprise/business (at a 'workplace') would need to comply with the rope diameter stipulations for each iteration of the GriGri. Insurance would be void if caught using any device outside of its design parameters.
Recreational users who are not a business enterprise and not considered to be at a 'workplace' can bend the rules at their own risk. Obviously your mileage will vary according to the rope condition and rope design characteristics. Would be 'wise' to test under controlled conditions to confirm how your device will perform before entrusting a life with sub-diameter ropes (eg a 9.8mm rope in a 10mm rated device).

Actually it was originally certified for 10.2 to 11mm, but Petzl did later re-certify it for 9.8 (only on paper, the stamped diameters stayed the same).

As for the OP.

Yes, even sub 9mm ropes will likely lock on the original GriGri... and as long as you remember that GriGri is not auto-locking, but assisted locking/braking you'll be fine.

In fact, I prefer my original GriGri with 9-9.5mm ropes as it pays out rope smoothy and still locks on sudden jolt.

You'll be absolutely fine on a 9.8mm with an original GriGri. I've been using mine for a decade on that sort of diameter as have thousands and thousands of other climbers. (I do have a 2019 GriGri but I still use my original one in preference.) 

I also regularly use mine down as low as 9.2mm without the slightest problem. 

However, I've heard, third hand admittedly, of situations where original GriGris haven't locked properly on really skinny ropes so some caution is warranted as you get closer to 9.0mm and I wouldn't use one on anything thinner. 

There's actually a 7mm version of the Mk1 for abseiling and the internals are unchanged.

I used mine for years with a 9.4mm Beal stinger with no issues although it's not rated for such a skinny rope. 

It'll work fine on 9.8. Maybe that very small chance of it failing to cam is ever so slightly higher than with a 10mm rope, but Grigris shouldn't be regarded as 100% anyway, whatever the model or rope diameter - you still need a hand on the dead rope at all times.